An online petition calling on UK Prime Minister Tony Blair to abandon plans for a road pricing system has amassed millions of signatures.

UK road pricing e-petition gets support

An online petition calling on UK Prime Minister Tony Blair to abandon plans for a national vehicle tracking and road pricing system closes on Tuesday having amassed more than 1.6 million signatures.

The experimental "e-petition", hosted on Blair's 10 Downing Street Web site, has garnered huge publicity and support since it first appeared, forcing the prime minister to promise to send an email to all signatories.

"Over the next few days I will be sending out a response to everyone who has signed the petition against road charging explaining the problems the country faces and why I believe road pricing is surely part of the answer here as it is in many other countries," Blair wrote in the Observer newspaper.

"I'm not kidding myself that this will change people's views overnight."

The petition was submitted by Peter Roberts of the Association of British Drivers (ABD) calling on Blair to abandon road pricing and instead "concentrate on improving our roads to reduce congestion".

It described the government's plans as "sinister and wrong".

Under the proposals, motorists would be charged for every mile they drive, using satellite tracking technology, with prices depending on the location and the time of day in a bid to counter a growing congestion problem.

Despite the furore caused by the petition, the government has vowed to press ahead with road-pricing trials.

"The government have already made up their minds that national road pricing is going to happen," said ABD spokesman Nigel Humphries.

"Infrastructure and laws are already being put into place - the wheels are already turning.

"Protestations that nothing has been decided and accusations that the public have been duped into signing the petition by false information are spin doctoring of the worst kind."

Blair's spokesman said details of the prime minister's response would be given on Wednesday but the government fully welcomed a debate on congestion.

"People have strong opinions. What's important is that we address those strong opinions as we attempt to come up with a solution," he said.

Initial estimates suggest a tracking scheme could cost drivers up to STG1.34 ($A3.33) pounds a mile to drive in the busiest areas at rush hour.

Transport chiefs argue that unless radical action is taken there will be gridlock on some of Britain's roads in 20 to 30 years.

Last December a government-sponsored report on transport led by former British Airways chief Rod Eddington said charging motorists to use roads was the only viable option.